The present technology relates to a display panel including a light emitting element, for example, such as an organic EL (Electro Luminescence) element for each pixel, a display device including the display panel and an electronic apparatus.
In recent years, in the field of display device which performs an image display, as a light emitting element of a pixel, a display device using a current driving type light emitting element, for example, the organic EL element, in which the light emitting luminance is changed according to a flowing current value, has been developed and promoted to commercialization. The organic EL element is different from a liquid crystal element or the like and is a self-light emitting element. Therefore, since it is not necessary for a display device using the organic EL element (an organic EL display device) to have a light source (backlight), it is possible for it to be thinner and have a higher luminance than a liquid crystal display device with a light source.
Here, generally, the current-voltage (I-V) characteristics of the organic EL element are degraded (time degradation) according to time course. In a pixel circuit in which the organic EL element is driven by the current, when I-V characteristics of the organic EL element are changed according to time course, since the partial pressure ratio of the organic EL element and a driving transistor connected to the organic EL element in series is changed, a voltage between a gate and a source of the driving transistor is also changed. As a result, since the current value which flows to a driving transistor is changed, a current value which flows to the organic EL element is also changed and the light emitting luminance is also changed according to the current value.
In addition, there are cases when the threshold voltage (Vth) of the driving transistor and the mobility (μ) are changed according to time course and Vth and μ are different for each pixel circuit due to the variability in a manufacturing process. In a case where Vth and μ of the driving transistor are different for each pixel circuit, since the current value which flows to the driving transistor varies for each pixel circuit, even though the same voltage is applied to the gate of the driving transistor, the light emitting luminance of the organic EL element is varied and the uniformity of a screen is impaired.
Here, even though I-V characteristics of the organic EL element are changed according to time course and Vth and μ of the driving transistor are changed according to time course, a display device in which the compensation function with respect to the change of I-V characteristics of the organic EL element and the correction function with respect to the change of Vth and μ of the driving transistor in order to maintain the uniform light emitting luminance of the organic EL element without being affected thereby are incorporated, has been developed (for example, refer to Japanese Unexamined Patent Application Publication No. 2008-083272).